Knowledge Base

F

Cipher Suite: TLS_­GOSTR341112_­256_­WITH_­28147_­CNT_­IMIT

Summary

code:
(0xc1, 0x02)
IANA Name:
TLS_GOSTR341112_256_WITH_28147_CNT_IMIT

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Components

B
Key Exchange Method
Name
GOST R 34.11-2012
Security
The GOST R 34.10-2012 (key exchange algorithm)[411] is a variant of Diffie-Hellman[269][270][271][272][273] key exchange based on elliptic-curve cryptography[259][260][261][262] and GOST R 34.11-2012 (hash function)[74]. The algorithm produces key encryption key (KEK) from the sender's private key and the recipient's public key (or the reverse of the latter pair and the user keying material (UKM). The algorithm can be used for static and ephemeral keys where one side uses a static key and the other uses an ephemeral one. Key exchange method can have forward secrecy[135][136][137][138], and does protect past sessions against future compromises. If long-term secret keys or passwords are compromised, encrypted communications and sessions recorded in the past cannot be retrieved and decrypted. Leading client applications do not use this algorithm. Unless your application or requirements specifically call for their use, it is generally safer to avoid cipher suites that are not adopted and supported by a critical mass of the industry.
Recommendations
Always prefer cipher suites with PFS property over the non-PFS ones. Note that performance considerations implies preferring Ephemeral Elliptic-curve Diffie–Hellman[91][92] over Ephemeral Diffie-Hellman[142][143][144][145].
B
Authentication Method
Name
GOST R 34.10-2012 (256)
Security
The GOST R 34.11-2012[453] is a digital signature[231][232][233][234] algorithm, part of the Russian GOST[185][186][187][188] standard, using elliptic-curve cryptography[259][260][261][262]. Leading client applications do not use this algorithm. Unless your application or requirements specifically call for their use, it is generally safer to avoid cipher suites that are not adopted and supported by a critical mass of the industry.
Recommendations
If your application or requirements specifically call for the use of algorithms which are not used by the leading client applications set the cipher suite order explicitly and cipher suites used by the leading client applications be preferred over the ones which do not used by them.
F
Encryption Type
Name
GOST 28147-89
Security
Encryption algorithm GOST 28147-89[516][517] is a block cipher[524][525][526][527] which was originally designed by the KGB[528], now part of the GOST[185][186][187][188] standards maintained by the Euro Asian Council for Standardization, Metrology and Certification[189]. The encryption algorithm is considered insecure[5][6][7][8], but leading client applications do not use this algorithm. Unless your application or requirements specifically call for their use, it is generally safer to avoid cipher suites that are not adopted and supported by a critical mass of the industry.
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server.
B
Encryption Mode
Name
GOST Counter (CNT)
Security
The counter encryption[105] is a block cipher mode of operation[293][294][295][296][297]. It does not provide authenticated encryption[563] which simultaneously assure the confidentiality[198][199][200] and authenticity[201][202][203] of data.
Recommendations
If your application or requirements specifically call for the use of a message authentication code[128][129][130][131] that does not provide authenticated encryption[563] prefer block cipher mode of operation[293][294][295][296][297] (eg: counter with CBC-MAC[266][267][268], Galois/Counter Mode[65][66][67][68] or message authentication code[128][129][130][131] (eg: Poly1305[289][290]) that proved authenticated encryption over the ones which does not provide it.
D
Encryption Key Size
Name
64
Security
Any symmetric key[193][194][195] with key size[438] less than 128 bits are disallowed by National Institute of Standards and Technology[428][429] as it is vulnerable to preimage attack[215] in theory. It cannot reliably prove that message came from the stated sender (its authenticity) and has not been changed, so connection is open for a man-in-the-middle attack[414].
Recommendations
Remove the cipher suite from the list of cipher suites supported by your server.
A+
Encryption Block Size
Name
256
Security
The block cipher[524][525][526][527] uses a block size[409] larger than 64 bits, so it is not vulnerable to sweet32 attack[496][497][498][499].
Recommendations
C
Message Authentication Code
Name
MAC GOST 28147-89
Security
message authentication code[128][129][130][131] is a hashed message authentication code[418][419][420][421][422][423][424] which is considered secure. The underlaying cryptographic hash function[510][511][512][513] (GOST 28147-89 "imitovstavka"[256] has weaknesses in it's design principles[413], however it is vulnerable to collision attack[566] and to preimage attack[215] in theory. It does not provide authenticated encryption[563] which simultaneously assure the confidentiality[198][199][200] and authenticity[201][202][203] of data.
Recommendations
Leading client applications do not use this type of message authentication code[128][129][130][131]. Unless your application or requirements specifically call for their use, it is generally safer to avoid cipher suites that are not adopted and supported by a critical mass of the industry. If your application or requirements specifically call for the use of that encryption algorithm prefer a message authentication code[128][129][130][131] that does provide authenticated encryption[563] prefer cipher suites that are adopted and supported by a critical mass of the industry, like message authentication code[128][129][130][131] Poly1305[289][290] that proved authenticated encryption or block cipher mode of operation[293][294][295][296][297] counter with CBC-MAC[266][267][268] or Galois/Counter Mode[65][66][67][68] or which also provides authenticated encryption[563]. In case of a hashed message authentication code[418][419][420][421][422][423][424] prefer message authentication code[128][129][130][131] based on Secure Hash Algorithm 2[71][72][73] over the ones based on other cryptographic hash function[510][511][512][513].